Gas turbines are widely used in commercial operations for power generation. FIG. 1 illustrates a typical gas turbine 10 known in the art. As shown in FIG. 1, the gas turbine 10 generally includes a compressor 12 at the front, one or more combustors 14 around the middle, and a turbine 16 at the rear. The compressor 12 and the turbine 16 typically share a common rotor 18.
The compressor 12 includes multiple stages of compressor blades 20 attached to the rotor 18. Ambient air, as a working fluid, enters an inlet 22 of the compressor 12, and rotation of the compressor blades 20 progressively compresses the working fluid. Some of the compressed working fluid is extracted from the compressor 12 through extraction plots 23 for other use, and the remainder of the working fluid exits the compressor 12 and flows to the combustors 14.
The working fluid mixes with fuel in the combustors 14, and the mixture ignites to generate combustion gases having a high temperature, pressure, and velocity. The combustion gases exit the combustors 14 and flow to the turbine 16 where they expand to produce work.
Compression of the ambient air in the compressor 12 produces an axial force on the rotor 18 in a forward direction, toward the compressor inlet 22. Expansion of the combustion gases in the turbine 16 produces an axial force on the rotor 18 in an aft direction, toward the turbine exhaust 24. A thrust bearing 26 at the front of the gas turbine 10 holds the rotor 18 in place and prevents axial movement of the rotor 18. To reduce the net axial thrust on the rotor 18, and thus the size and associated cost of the thrust bearing 26, the gas turbine 10 is typically designed so that the axial forces generated by the compressor 12 and the turbine 16 are approximately equal but opposite.
Various commercial processes generate effluent process gases. For example, chemical processes at oil fields generate substantial quantities of pressurized oxygen, carbon dioxide, or nitrogen as effluent process gases. The effluent process gases are transferred for storage and/or ultimate disposal.
The costs associated with the collection, storage, and disposal of the process gases may be considerable, and various attempts have been made to operate a gas turbine system using process gases. However, the process gases have different molecular weights, compressibility, flammability, and other physical characteristics than ambient air, for which the gas turbine is designed. Therefore, the need exists for a gas turbine that can operate using effluent process gases created by commercial operations.